Multiple automatic welder



March 10, 1936. w, T

MULTIPLE AUTOMATIC WELDER Filed Sept. 28' 1933 5 Sheets-Sheet 1 March 10, 1936. H. w. ROTH 2,033,851

MULT I PLE AUT OMAT I C WELDER Filed Sept. 28 1933 5 Sheets-Shee't 2 f)enzy Zu. Rolb W, /PI;LLIAMJE H. N. ROTE! MULT I PLE AUTOMAT I C WELDER Mamh W Filed Sept. 28, 1955 5 Sheets-Sheet di totuotf March 10, 1936.

H. W. ROTH MULTIPLE AUTOMATIC WELDER Filed Sept. 28{1935 5 Sheets-Sheet 4 March 10, 1936. H, w ROTH 2,033851 MULTIPLE AUTOMATIC WELDER Filed Sept. 28, 1933 5 Sheets-Sheet 5 LIMITEDIME QELAY Patented Man. 10, 1936 UNITED STATES PATENT OFFICE MULTIPLE AUTOMATIC WELDER Michigan Application September 28, 1933, Serial 65i,305

16 Claims.

My invention has for its object to produce a welding machine that is provided With a plurality of electric welding devices that may be mounted. in close relation so each other and so disposed as to produce wcded areas along any desired lin6 01 lines, means being provicled for so mounting the welding devices, that the line of weld may extend curvedly o1 straight or in broken lines or in separate lines and two or more pieces of sheet metal may be welded into an integral structure. The invention is particularly f advantage when used for welding plates together which have been die pressed to form curved surfaces, such as in forming automoblle bodies o1 automobile sheet metal parts.

The invention provides a, machine whereby a number of plates, two or more, may be welded together along their contacting edge porhions in a single complete operation of the machine, to form a sheet metal structure of any form and usable for any purpose.

The invention also provides a means for' electrica11y welding along stralght 'or curved or irregular or separated lines by the sequential operation of a plurality of welclers, means being provided for directing the source of supply cf eurrent to the members in sequence anal enabling utilization of a relatively low pressure means ancl a relatively small curreno that may be supplied by a single pump and a, Single transformer. Tims the invention provides a substantially continuous welcling operation tluoughout Lhe contacting areas of two or more plates.

The invention also provides automatic means for producing a rapid sequential operation of the welders whereby each successive contiguous welding area Will be produced upon the completion of the welding of thie preceding area.

'Ihe invention also consists in providing Conjunctively usable We1ders of diiferent forms to enable closely disposed welds in struct-ure-s that by reason of their configuration require difierent forms of welders to procluce the integrated unlon required to produce a completed sheet metal structure in a single operation of the welcling machine.

The invention also consists in means for producing ehe requirecl sequential pressure in aalvance of each sequential closing of i:he primary circui of the transformer to produce the resul ant 10W potential ancl high amperage through the weldir'1g pbint in concact with the work.

Ehe invention consists in other feaures and a-slvantages which Will appear from Ehe following description and upon examination of the drawings. Structur es containing the invention may partake of different forms and may be varied in their details and still embody the invention.

- T0 illustrate a practical application of the invention, I have selected a welding machine embodying the invention as an example of the va- .rious structures and the details of such structures that contain the invention, and shall clescribe the selected structure and a modifiecl form 0f Welder hereinafter, it being understood that variations may be made and that certain features of my invention may be used to advantage without a corresponding use of other features of alle invention, ancl without departing from the spirit of the invention. 'Ihe particular structure selectecl and the modified form of welding member are shown in the accompanyingdrawmgs.

Fig. 1 of the drawings illustrates an ass6mbly view 01 material parts 0f the machine that may be utilized for welding a piuraliuy 0f sheets together. Fig. 1 is merely illustrative of assembled parts of a machine containing the invention. Fig. 2 illustrates a tank of oil controlling valves and the mechanism for sequentially operating the valves. Fig. 3 is a top view of the device illustrated in Fig. 2. Fig. 4 is an end. view of a valve controlling mechanism. Flg. 5 illustrates an enlarged. view of a, part of the mechanism shown in Fig. 2, portions of which are shown in section. Fig. 6 illustrates a piston valve for controlling the valve actuating mechanism. Fig. 7 illustrates the connection between one of the welding members and the valve comtrolling mechanism. Fig. 8 illustrates a modified form of a welding member whieh is particularly adapted for use unde1 a ledge o1 in a small corner or space. Fig. 9 illustrates, diagrammatically, the electric and hydraulic connections of the parts of the apparatus.

In the form o1 machine illustrated in the drawings, the welclers l a.re provided With brackets 2 that may be conneoted t0 any suitable support, such as the bar 3, which is connected to a movable fi'ame 4 of a maahine. The welclers are provided With cylinders and pistons that operate the welcling points. 'Ihe movable frame 4 is raised and lowerecl as in the form of a la1ge press that supports and moves the parts that are connected hydraulically 01' pneumatically to the welders. 'lhe welders may thus be raised and lowered and thus located in operative relation with respect to thc work, that is, the plates l, that are supported 011 a heavy copper bar 8 locatecl, preferably, upon 2. fixed part of tnn machine.

bar 8 may be suitably reinforced 130 withstand the pressure to which the plates are subjected in the progressive welding operations produceol by the Welders I.

The supported bar 8 will necessarily conform to the shape of the line of contacting areas of the plates I that are to be welded together. Thus the bar 8 may be curved so as to correspond to the various shapes into which the plates may be formeol. Likewise, the bar 3 will be correspondingly bent 01' shaped and the brackets 2 may be cut to vary the location of the welders, w1th respect to the bar 3, and so a.s to permit movement of the movable part l oi' th e machine and to cause the welders to be axially located in lines that extend at right angles to the surfaces of the plates at the points where the Welding pomts of the welders may contact with the upper of the plates. The brackets 2 may be cut or grooved and welded to the bar 3 so locate the axes of the welders that the welder points Will strike the surfaces of the plates in directions that are at iight angles thereto.

The welders may partake of different forms and their welder points may be angularly disposed or disposed in non-alignment with the axes of the cylinders of the welders. They are, preferably, hydraulically operated which enables them to exert; a high pressure in a very short interval of time and produce welds at closely spaced points. By the use of 011 a.s a, medium of transmission a much higher pressure can be produced by a very small cylinder and piston. It also enables the use of a more positive pressure and the pressure is transmitted with greater rapidity in that it elimina.tes an extended compression period. Also, by the use of a, liquid, all rebound or kickback, other- Wise occurring when ehe pistons are released, is eliminated. Thus, where pneumatic cylinders are used the weld points have to be spaced 3 inches apart, while in connection With the use of hydiaulic welders they may be spaced 1 inoh apart. Also, by reason of the smallness of the hydraulic welders, they may be readily located in corners and welds may be made close corners. Also, by reason of the diameter of the Welders, they may be readily positioned at any angle and supported in closely arranged relation on curved bars for purposes of supporting the vvelders in position to produce closely positioned welds on curved surfaces of the oontacting portions of the plates arranged in any desired relation with respect to each other. Thus the welders may be readily arranged a1; all angles, and inside of overhanging portions 0I" and in pla.ces that are limited by reason of the shape of the sheet metal structure that is to be integrally formed by interwelding of the sheets together.

Also by the reason of the rapidity of the application of the pressure that is obtainable through the use of a liquid as a medium for transmission of pressure, the welds may be made with correspondingly great rapidity In machines comtaining the invention the welds are made ab the rate of three per second, while pneumatically operated welders require long period of time to reise the pressure to a proper welding pressure and delays the formation of each weld three or four seconds.

The fiow of the liquid to the welders is 001'1- trolled by a, plurality 015 valves that are sequentially operatd to direct the flow of liquid from a. source of supply under pressure to the welders in succession, means also being provided fo1 producing a low voltage ourrent through the 10W resistance circuit through the welding points of the welders in succession, and after the pressure fluid has created in each welder the required welding pressures.

The we1de1s I a.re connected to a bank of valves I2, supported. in a, plurality of blocks I3, that are tied together tolocate the valves in two rows. The valves are conneoted with tl1eir respective assooiated welders I through the tubes I4 and a means for sequentially operating the valves provided for causing the valves to open Ehe connecuion between the source of supply of liquid under pressure with the welclers am]. to close Ehe oonnections 311d subsequently open return connections to a reservoir. Between the operations of each valve a suitable high amperage cu1rent is caused to pass through the contacting portions of the plates at the welder point i;o produce the weid.

Each welder I is provided With a cylinder I8 that may be threaded into the encls of the bracket pa1ts 2, and a piston bearing member, 01 bushing, I9, may also be threaded into the braoket part 2. The bushing I9 forms a suitable bearing for the piston rod 20 having ab its upper end the leather cup piston 2I located in the cylinder I8. The tube Hi is connected to the upper end of the cylinder I8 and to that particular portion of the block I3 having the valve I2 that is associated with' the welder. Whenthe valve I2 is moved it opens the source of supply of liquid under raressure to the cylinder I8 a.nd the. oressure of the fiuid causes the piston 2I 130 de.scend.

A spring 22 is located in che cylinder I8 and intermediate the piston 2I end the bushing I9, anol operates to cause the rei;urn of the piston 2I, when the pressure in the cylinder I8 is released by a return movement of the valve I2, which permits the liquid Within the cylinder I8 to return 1:0 the source of supply of the liquid, that is, to a reservoir. The spring 22 thus causes the welder poini; 23 to be raised from the work. The welders may be constructed to fit the conditions in which they are to be used and thus may partake of different forms. In the form shown in Fig. 7 the welder points 23 are connected to the piston rods 20 by a. suitable threaded counector 24 that also operates to clamp the flexible 10W resistance conductor 25 -anal establish connection between the conductor 25 and ehe welder point 23. A metal sleeve 29 is located on the piston rod 20 and is provided with a flanged end 30. It extends through the bushing I9 and abuts the piston and a disc or washer 3I. A sleeve of insulating material 32 is located Within the sleeve 29 and a disc of insulating material 33 is located exterior to the metal disc or washer 3I. The insulating sleeve 32 extends from the leather cup 2I to the insulating disc 33 end so as so completely electrically insulate the piston from the cylinder I3 and conse-quently the insulating sleeve and the disc prevent pitting of the piston rod, particularly ab the point that lt passes through the bushing I 9. When the connector 24 is threaded onto the piston rod 20, it engages the end of the flexible conductor 25 and operating through the upper end of the piston rod, the metal sleeve 29 anal the metal disc 3I, the end of the flexible conductor 25 is secured in position anal electrically connected with the welder point 23.

In order to prevent disconnection and rotation of the piston 20, a suitable piu 34 m-ay be inserted in the end of the flexible conductor 25 whare it is clamped by the sleeve 24 and so as to locate an end portion of the pin 36 in a, slot 35 formed in the piston rod 20.

In Order that the Welders may be located in spaces that are limited by reason of the forms of the struotures that are to be produced such as in closely confined spaces as under the cowl 2,oss,ss1

of an automobile and in corners that require overhanging of the welding points from the cylinders or the brackets, they may be formed 130 operate in difierent ways to produce the requ ired:

pressure in advance of the introduction f the relatively large welding current. In the form of construction illustrated in Fig. 8, the welder is supported on the bracket 2 that may be constructed and supported in substantially the same way that the bracket 2 of the form of we1der illustrated in the other figures. Likewise, I;he cylinder I8 and the piston rod 20 may be in,- su1atedly supported and connected in operative relation to each other and so as to produoe movement of the pi'ston 21 by the pressure that is transmitted through ehe tube I I Which is connected to its associated valve located. in the assembled blocks I3.

In order that; the welder may produce a pressure in a direction in non-alignment with the axis of the cylinder, a block I28 is pivota1ly supported on a yoke I29 that may be connected 130 the bracket 2, such as by the adjustable threaded pin I3II and the locking nut I3I. The block I28 is connected to the piston I20 by means of 2.1ink I32 and when the piston 2I is depressed by the pressure of the 011 transmitted through the tube I4, the block I28 will be swung on its fulcrum pin I33 and be pressed against the W01'k I. The welder point I34 is connected to the block I28 and.through the block 128 I;o the conductor 25. A plurality of welders, of the form shown in Fig. 8 may be used together er any number in conjunction with welders, of the form shown in Fig. '7 and controlled and caused to' operate sequentia1ly by the valves I2.

Each valve I2 comprises a stem 38 having portions cut therefrom to form the passageways 39 and II) Within the bores II in the b10cks I3 in which the stems 38 are located. The passageways 39 and 40 are separated by the portion 42 of the stem 38 that has substantially the fu11 diameter of the bore 4I and in which the valve stem is located, and forms a piston part that separates the passageways 39 and 40.

The stem 38 is normally supported in a position to locate the piston part 42 of the stem at a point 130 establish connection between the cylinder I8 of its associated welder with the reservoir 0f oi1 45. The stem is yeldingly he1d in this position by means of the spring 45. The 1ower ends of the stems 38 extend throug h the b1ocks d'r that have passageways 39 that communicate vviish the passageway 48 and provide fo1 fu1l return 0f the 011 to the reservoir when the valve stems are raised by the springs. The 10W- er end of the stem is threaded and the movement of the stem by the operation of the spring 46 is limited by means 01 the nuts 48 that may be threaded onto the stem 38.

The piston 2I and the we1der point 23 are subject to the pressure created by a suitable pump 58 that may Ioe electrically driven by a suitable motor that may be connected to the shaft I. Preferably, the pump 59 is located within one end of the reservoir 45 from which it draws ehe 011 and directs II; to the pipe 52 through whioh the pressure is transmitted to the passageway formed in the blocks I3. The passageway 53 is formed by registering bores made in the plugs I3. The end of the passageway 53 through the blocks may be closed by a suitable plug 55.

The blocks I3 are suitably tied together by means of the rods 54 and the nuts 55, suitable packing being provided to prevent the escape of the 011 from between the contacting faces of the blocks I 3. Thus any number of blocks having the valves I2 may be readi1y assambled or dismantled to provide for the control of any number 01 welders. The supporting bar 3 is made to conform to the contour of the overlapping or comtacting portions of the sheets I, anal t's1e couductor 8 is likewise made to conform to the 001'1- figuraoion of the contac-ting portions of I:he sheet. The welders are joined to the supporting bar 3 to locate the welder points along the required welding ]ine and position them so that the welder points Will, when depressed, move against the upper plate I in a direction that is substantially at1ight; angles to the surface of the plate at the point where it makes contact. The weldc1s a1e then connected hydraulically to the b1ocks I3 so as to Ioe controlled by the valve and electrr'cally to the conductor bar 26 which may also be comvc-niently formed to establish connections With ehe conduoors 25 and thus may be made t-o roughly conform With the contour 01 the overlapping portions of the plates I.

When any one of the valves is ope1ated as by depression of a stem 38 against the pressure of the spring 35, the pressure created by the pump 52 is transrnitted immediately through the pipe M to the piston 25 of the corresponding welder anal causes the we1der point 23 to immediately tightly press the work against the conductor bar 8. When, therefore, the circuit of the primary is completed, a current of large amperage passes through the welder points and by reason of the consact resistance of the meta1 of the plates I, the weld is produced in the manner we1l known in the art. The current through the traneforzuer is immediately opened and this is followed by the release of the pressure of the fiuid and the immediate release of the plates I and withdrawal of the welder point.

The sequential operations of the valves I2. and the contro1 of the circuit of the primary seil of the transformer are attained by any suit bie mechanica! or electrornagnetic means that ma v be operatively connectecl to the stems 38 0f the VFJTGS to cause their sequential operations, means boing provided for closing a switch in the circuit of the primary coil of a transformer upon, o1 short 1y after, the operation of each va1ve. The circuit of the primary may be completed by a. time relay, of the type well known in the art, that phlegmatically operates to complete the circui of the primary coil upon the passage of a eurrent through the con-trolling coil of the re1ay und after the expiration of a very shott tims interval. 'Ihis is followed by a period of c1osure and then automatic opening movernent of Ihe relay. The circuit of the controlling coil cf the relay may be completed by contacts conneted t0 the va1ve sterns ancI thus initiated in i'i=. operation upon operai;ion of any one of the valves.

The va1ve operating meohanism, in the particular forrn of construction shown in ihe dramings, cornprises a, screw 55 that may be operated by a suitable reversible air motor EI, indicated G diagramrnatically in Fig. 9, and Which may be connected to I;he shaft 82. The shaft 62 is comneced by suitable beveled gears 63 with the screw SEI. A traveler 6 I, having a threaded part 59,

is shifted over the bank of va1ves I2 by rneans that prevent limited rotation of the pivoted cams in one direction. The cams 65 and 66 are supported on the traveler 66 so as to engage the upper ends of the stems 38 of the valves and. sequentially depress them as the traveler 64 is moved back and forth over the blocks I3. The valves are arranged along two parallel lines and the cam 65 is located so that it Will operate the valves arranged on one side of the passageways 53, while che oam 66 Is supported. so as to operate the valves located on the other side of the passageway 53. Limiting stops of the cam 65 are such as to hold the cam 65 as against rotation as it is carried over the ends of the valve stems locate-d on one side of the passageway 53, buc upon return movenient of the traveler 66, the cam 65 rotates relative to the trave1er 66 so as to ride over the ends of the valve stems without depressing them while the other cam 66 is held in position by its limiting stop so as to cause the valve sten1s of ehe other slde 0f the passageway 130 be sequentially depressed, and again upon the reverse movement of the traveler 66 the cam 66 merely rides without depressing the valve stems associated therewith, while the valve 65 is operated to depress sequentially the valve stems associated therewith.

In the form of construction shown, each c;am 65 and 66 is provided With a projecting portion 61 and the traveler 66 is provided with adjustlng pins 68 that are adapted to engage the projecting portion 61 and may be utilized for not on1y limiting the movement of thc cams so as t0- hold them in position to cause the sequential operation of the valves, but also rnay be adjusted to adjust I;he extent of the depressed movement of tne valves to produce the desired stroke of the valve stems. Thus the cams operate to sequentially connect the cylinders I8 of the welders I with the fluid under pressure that is transmitted through the tube I4 from the passageway 36.

The movement 0f the traveler 64 is controlled by means of the air valve II. The air valve II has a piston member I2 located within a shell I3. The shell I3 has an air inlet port I4 and the outlet ports 15 and 76. The p-ison I2 operates to either close the inlet port I4 01' so connect the inlet port I4 either With the outlet port I5 or I;he outlet port I6, according I:o oneof the three positions that; may be taken by the piston 12. The piston I2 is provided With a stem 'I'I for movi ng the piston inwardly wirh respect to the Shell I3. A spring 18 is located Within the shell and around a guiding stem I9 for the purpose of moving the piston I2 counter to the movement procluced by the stem 'I'I.

A suitable source of supply of air under pressu1e, such as a suitable air pump is connected to the port 74 by means of the taube 86 and the ports 75 and I6 are connected 130 a suitable reversible air motor by means of the pipes 8I and 82. When, therefore, the piston 12 cf the valve II is moved to one position, the ai1 motor that drives the shaft 62 is caused to rotate in one direction and When the piston I2 takes a second position, the air motor is causecl 130 drive the shaft 62 in the opposite direction and when the piston I2 takes a. neutral position so es to close the port 14 of the valve II, the motor ceases its operation.

The positions 0f the piston and consequently the operation-of the valve II 130 control the movement of the traveler 64 am obtained through the actuation of the stem 'I'I. The stem 'I'I cf the piston is provided With a pair of grooves and a projecting end portion- 86 that may be used for manually operating the piston 12. A spring pressed latch 81 is pivotally supported 011 a bracket 88 and has a projecting nose 86 that is adapted to engage in the groove 85. The latch 87 operates to hold the piston I2 in the position 130 which the stem 'I'I may be moved. Initially the traveler 66 is located ab the end of I:he screw 66 where it is connected to the bevel gear wheels 63. The sem 'I'I is pushed in manually by pressure against the handle end portion 86 of the stem, which causes the nose 89, which initially rldes 011 the cylindrical part 98 o f I;he stem 'I'I, to drop in I;he groove 85. This est-ablishes connection between the ports I I and I5 and causes the all motor to rotate the screw 66 in a direction to move the trave1er 64 to the opposite and of the screw that is, to the ned located near the valve II. The traveler 66 is provided With a rod 92 adjustably secured in position for engaging the latch 81 and operates the latch to release tne stem 'I'I. The spring 18 operates to move the piston 72 to establish connection between the ports I4 and I6 and cause the motor 130 move in a reverse di1ection. As the traveler 66 approaches the end cf the screw 66, namely, that in proximity to ehe gear box having the gear wnee1s 63, it engages an adjustable screw 93 that is connected by a bracket 95 to the rcd 95. The rod 95 is connected to an arm 66 that has a slot formed in one end through which the end portion 86, cf ehe stem 'I'I, extends. A suitable nut 67 is acljustably looated. on the stem 'II and is engaged by the end of the arm 96 I;o= push the piston I2 to ics neutral position and close the inlet port I5 and stop the air motor. The piston 72 is held in this position against the pressure of the spring 78 by the traveler. When the stem I? is manually manipulated to force the stem inward until the nose 69 of tne latch 81 engages in the groove 85 and holds the piston in position to cause the traveler 66 to move over the valves, causing operation of one set of valves and upon reversal of the valve II and return movement of the traveler 64, it Will cause ehe operation of the other set of valves and the resultant sequential operation of the welders controlled by the valves.

In order that the valve stems may be readily depressed by the inclined surfaces IIII, of ehe cams 65 and 66, the ends of the stems of the valves are provided with balls Ill2 that may be secured by fianged ovcr edges of recesses formed. in the upper ends of the stems andthus secured in position.* The ba1ls I62 Will oprate reduce the frictin cf the mechanism operative t0 depress the stems.

T0 produce separation of the sediment in the 011 that forms in the use of .the machine, the reservoir 65 may be provided With a partioning wall II3 which Will afiord an opportuniby for the sediment to settle in the chamber IM in Which I;he ends of the valve stem extend. The uppcr end of the partitioning wall I03 is provided with an opening I 05 that may be covered by a suitable screen III6 which Will prevent the m-ovexnent of the sediment charged oil and will prevent air charged oil from entering the chamber III'I in which the pump 50 is loeated.

The lower end of e ach stem 38 is provided with a contact III] that may be formecl to have an elastic spring pa1t III and a socket II2. The socket II 2 may be threaded onto the end cf the stem 38 secure the contact III) in position. The elastic part; III enables variation in movement of I:he stem While the contact I II) is in sontact with the contact bar II 3. The contact bar H3 is supported, preferably, below the surface 01 the 011 -in the chamber IM of the reservoir 45. Submergence of the bar II3 and the contacts III) in the oil reduces arcing and burning at the breaks of the contact when the stems are released. Preferably, the contacts of the stems are separated by Walls II4 forming stallsv in which a pair of thebontacts of the Sterns are separated from adjoining contacts. 'Ihe conductor bar II3 is suitably insulated from the brackets II5 by means of Which they are supported on the assembled b1ocks I3. Suitab1e conductors II I are connected t the conductor bar I I3 and the frame and are then connected to the conductor bar II3 and the contacts I III.

The conductor bar, as shown in the diagram in Fig. 9, is connected 130 the limited time relay II8 and to one of the main lines I I9. The other of the main 1ines II9 may be connected to the assembled blocks I3 whereby a circuit will be completed through the limited time re1ay I I8 when contact is made between the conductor bar II 3 and one of the contacts III]. This Will occur each time a valve ste1n is depressed by the operation 0f one of the cams. The limited time relay closes a cir'cuit through the coi1 I2I) which electromagnetically operates the double-pole switch I2I to c1ose the circuit of the primary coi1 I22 of the transformer I23. The secondary coil is a 10W resistance coil having but a turn or two, which is connected to the conductors 25 of the we1ders anal to the conductor bar 8 of the machine. 'I'he circuit through the primary coil t0 the mein 1ines II9, however, is not vcompleted by reason of the delayed action of the limited time relay III! unti1 after one of the welder points 23 has been pressed against the sheet meta1 to press contacting portions of the sheets agsinst the conductor bar 8. The limited time relay I I8 is set to release automatically, its armature I 24 in a very short time after the switch I2I has been c1osed by its operation. 'Ihe limited time reiay is so Set as to perfo1m this closing anal opening movement during the period that the surfaces I25 of the cams 65 and 65 ride over the ends of the stems 38 of the va1ves so that in advance of release of each of the valves by the cams, the circuit 0f the primary of the transformer I23 is epened and upon re1easement of the valve, its ass-3Ciated welder has m0veci its welder point avvay from the p1ates.

By reason of the fact that the welders a1e hydraulically operated and the pressure is immediately transmitted through the mediurn of the oi1 in the tube M, to the pistons 2I, and the time relay is set for closu1e as soon as the welding points are pressed against thefivork and immediately upon the rise of the temperature to enable a perfect weld without burning, the time re1ay opens the primary circuit. Shortly thereafter, giving opportunity fcr the bot metal to set anti the weld to draw, the Welding point is then raised. These operations occur in an exceedingly short interval of time and can be readily gauged by adjustment of the time limit relay. 'I'he machine will consequently produce the weids exceedingly rapidly and each Weld Will be accurately anci perfectly formed. It is, however possible to simplify the design 0f the machine and to avoid the timin-g reiay by using the movement cf the valves to direct1y determine the welding tirne. In this instance the speed of the traveller will Control the welding time. In many instances it may be necessary t0 we1d various thicknesses of metal in the same machine. The machine should there- Tore adjust itself from spot to spot to take care of the variations in thickness. My invention makes this possible by applying means to auto matically vary the speed of the traveller or the voltage of the welding current, while the machine is in operation. For this purpose, f0r instance, acljustable contacts may be arranged in the way of the traveller, these contacts to operate a checking valve (to influence the speed of the air motor) 01 a throw-over switch (to change the number of primary turns). Thus it is possib1e to automatically change the We1ding time 0r welding current, when the traveller operates a certain preselected valve.

I claim:

l. In a, welding machine, a plurality of welders each having a cylinder and a piston, and a. weltling point operated by the pressure of the fluid in the cylinder, a source of supp1y of fluid under,

pressure, a source of supply of electric current, means for sequentially connecting the cylinders With the said source of supply of fluid pressure, and means for connecting the said welding points With the said source 01 supply 0f current sequentially, each welded point being connected with the source of supply of current during the periods 0f connection of its associated cylinder With the source of supply of fluid.

2. In a welding machine, a plurality of welders each having a cylinder and a piston and a weiding point operated by the pressure of the fiuid in the cylinder, a source of supply of fiuid under pressure, a source of supply of electric current, means for connecting and disconnecting the cylinders with the said source of supply of fiuid. pressure, and means for connecting anti disconnecting the said Welding points With the said. source 0f supply of electric current, the last named means operative to connect and disconnect each we1der point intermediate the connection and disconnection of its associated cylinder, the said means operative to connect the welders in succession t0 the source of supp1y of fiuid pressure and t0 the source of supply of electric current acting sequentially.

3. In a welding machine, a plurality of We1ders each having a cylinder and a piston and a weiding point operated by the pressure of the fluid in the cylinder, a source 0I" supply of fluid under pressure, a source of supp1y 01 electric current, a valve fo1 controlling the flow of the fiuid f1om the said source of fiuid pressure to each welder, and a circuit closing means for producing a eurrent through the welding point upon operation oi each of the said valves, and means for sequentiel- 1y operating the said valves 4. In a we1ding machine, a plurality 01 weidere each having a cylinder and a, piston and aweiding point operated by the pressure of the fluid in the cylinder, a S0111C8 of supp1y of fiuid under pressure, a piurality of blocks, each of the blocks having a plurality of valves, the blocks having a common passageway and connected Wlt'n the source of supply 0f fiuid pressure, means f01 counecting the welders to the blocks, parts having passageways controlled by the said valves forconnecting the welders With the first named pas sageway, a source of supply of electlic current, a plurality of contacts, and means for operating the said contacts in conjunction with the operation of the seid valves for connecting the source 0f supply of e1ectric current With the said weiding points.

5. In a welding machine, a plurality of welders each having a cylinder and a piston and a we1ding point operated by the pressure of the fiuid in the cylinder, a source of supply of fiuid under pressure, a plurality of va1ves arranged in a1ignment for connectingthe welders to the gsa.id source of supply, a traveler, means for reciprocating the traveler, the traveler having means for operating the valves in sequence, contacts connected to the valves and movable therewith, a source of supply of electric current connected to the welding points and controlled by the movement of the said contacts.

6. In a welcling machine, a. plurality of welders each having a cylinder and a piston and a weltling point operated by the pressure of the fluid in the cylinder, a source of supply of fluid under pressure, a plurality of va1ves having movable valve members and divided into two sets, the valve members of each sei: arranged in parallel alignment, a traveler, means for reciprocating the traveler, the traveler having means for actuating the valve members sequentially in the reciprocatory movements of the traveler for connecting the welders in succession with the said source of supply of fluid under pressure, a source of supp1y of electric current, movable contacts cannected. to the valves, a contact bar forming a common fixed contact for said movable contacts for completing the circuit of the said source of supply through one of said movable contacts upon movement of any one of the valve members.

7. In a welding machine, a plurality of welders, each welder having a cylinder and a piston and a welding point operated by the pressure of the fiuid in the cylinder, a source of supply of fluid under pressure, valve members for controlling the flow of the fiuid to the said welders, a traveler having means for operating the valve members in sequence. a screw for reciprocating the traveler with reference to the valve members, a reversible fiuid motor for operating the screw, a valve for controlling the fluid motor, means for operating the valve to initiate movement 0f the traveler, and means for operating the v1ve to reverse the motor and 130 stop the motor.

8. In a welding machine, a plurality cf welders each having a cylinder and a piston and a welding point operated by the pressure of the fluid in the cylinder, a source of supply 015 fluid. under pressure, a. p1urality of blocks having passageways, means for securing the blocks together t0 locate the passageways in alignment, means for counecting the said passageways With the said source of supply 0f f1uid under pressure, an 011 reservoir, the blocks having passageways comnected 130 the reservoir and the first named passageways, the cylinders connected 110 the last named passageways, valve mernbers for controlling the last named passageways and arranged in two rows for connecting the welders with the first named passageway and With the reservoir, a source of supply of electric current, contacts 10- cated below the surface of the 011 in the reservoir for controlling the fiow of the current to the seid welding points, a traveler having means for operating the valve members in sequence, a

' screw for reciprocating the traveler with reference the valve members, a reversible fiuid motor for operating the screw, a valve for comtrolling the fluid motor, means for operating the valve to initiate movement of the traveler, and means for operating the va1ve to reverse the motor and to stop the motor.

9. In a welding machine, as set forth in claim 5, wheireby the movement; of the contacts directly determines the welding time.

10. In a welding machine 38 set forth in claim 5, including means t0 automatically vary the speed of. the traveller while the machine is in operation,

11. In a welding machine as Set forth in claim 5, including means to automatically vary the weldfing current while the machine is in operation.

12. In a welding machine, a plurallty of individual' welding units, each having a Welding point and a fiuid motor for pressing ehe same against the work, a source 0f supply of weldjng current and a control unit for said welding units comprising a source of supply of fiuid under pressure, a series of valves for respectively connecting and disconnecting the motors of the individual welding units with said source of supply of fiuid pressure, a traveler for operating said valves sequentially and a circuit closer associated. With each valve and actuated therewith to supply Welding cunent the welding point while in contact with the work and to cut off current in advance c f separation of said point from the work.

13. In a welding machine, a control unit for a plurality of individual fluid pressure operated welding units comprising a source of supply of. fluid under pressure, conduits for connecting the individual welding units with said source of supp1y of fluid pressure a series of valves for respectively controlling said conduits, an electric circuit closure associated with each va1ve and a traveler for operating said valves and associated circuit closures sequentially.

14. In a welding machine, a control unit for a plurality 0f individual fiuid actuated welding units comprising a plurality 0f blocks, each carrying a series of valves, said b1ocks being assembled in series so that the valves correspond in number to the individual welding units, a source of supply of fluid under pressure 130 all of said valves, an electric circuit closure asscciated With each valve 110 be operated therewith and a traveler for actuating said valves sequentially.

15. In a welding machine, a control unit for a plurality of individual fiuid operated. welding units comprising a source of supply 01 fluid under pressure tWo parallel series of valves for comtrolling the admission and exhaust of fluid to the individual welding units, a reciprocating travelerand means on said traveler for sequentially actuating the valves in the two series, the valves of one series being actuated by ehe traveler when moving in one direct-ion and that of the other series when moving in the reverse direction.

16. In a welding machine, a control unit for a plurality of. individual fiuid operated. welding units comprising a source of-supply o1 fluid under pressure, two parallel series of va1ves for comtrolling the admission and exhaust of fiuid to 13116 individual welding units a reciprocating braveler and rockable cams on said traveler for respectively traversing the valves of the two series .to sequentially actuate the same when moving in one direction and to ride over without actuation when moving in the reverse direction, the cam for one series actuating the valves thereof when the traveler is moving in one direction and the cam for the other series actuating the valves when the traveler .is moving in the reverse direction.

HENRY W. ROTE 

